Several different mufflers may be arranged in series in the exhaust system of a motor vehicle in particular. For example, a front muffler, a middle muffler and a rear muffler may be differentiated. A rear muffler is situated near an end pipe from which the exhaust is emitted to the environment. For example, such a rear muffler may include a housing containing an absorption chamber filled with an absorbent agent. A pipe carrying exhaust gas in the muffler is connected to the exhaust system or forms a part of an exhaust line of the exhaust system, passing through the housing and the absorption chamber. Inside the absorption chamber, a wall of this straight-through pipe is perforated, so that airborne sound entrained in the stream of exhaust gas can enter the absorption chamber and be absorbed in the absorbent material. This achieves a certain damping characteristic. In particular, middle frequencies and higher frequencies are muffled to a relatively great extent with this design, whereas lower frequencies are muffled only to a comparatively minor extent. This circumstance may be utilized for a targeted sound design.
In certain applications, e.g., in an exhaust system for an internal combustion engine of a motor vehicle, it may be desirable to reduce the sound pressure level of the lower frequencies while at the same time emphasizing the middle frequencies.